1. Field of Invention
The invention relates generally to the field of oil and gas production. More specifically, the present invention relates to a device used in treating a wellbore and reservoir. Yet more specifically, the present invention relates to a self-contained device disposable in a wellbore for treating components of the production flow path.
2. Description of Prior Art
Hydrocarbon producing subterranean formations may be treated in any number of ways. One way comprises gravel packing, which is typically used for unconsolidated reservoirs for sand control and may be used in open hole as well as cased hole environments. Gravel pack typically involves injecting a fine particulate matter such as sand or engineered proppants, also referred to as gravel, within the formation surrounding a hydrocarbon producing wellbore. Injecting this gravel into the formation under pressure provides a gravel pack, or a packed sand layer in the region of the formation surrounding the wellbore. The gravel pack prevents connate sand from making its way from the formation and into the wellbore. Isolating the sand from the production flow path in the wellbore enhances hydrocarbon production by not allowing contaminant matter into the wellbore that may hinder fluid production or destroy production hardware components.
After inserting the gravel into the formation, means for retaining the gravel in the formation may be employed, such as a screen or a slotted sleeve to maintain this material in the formation. Other modes of wellbore enhancements include treatment materials, such as stimulation fluids and/or acidizing fluids. These may be injected under pressure for promoting hydrocarbon production in a particular zone in the formation. Certain gels may also be inserted as needed; when excess water is being produced by a well, fluids for manipulating the permeability of the production flowpath may be inserted as well.
Generally these well treatment fluids are provided to the zone of treatment via a tubular member that extends from the reservoir region back to the surface. To overcome the pressure losses of the long tubing length and downhole hydrostatic pressure, a pumping system is typically employed at the surface. These pumping systems may be disposed within a service truck or self contained adjacent the opening of the wellbore. A substantial amount of fluid, in excess of what is actually injected into the treatment area, remains in the tubing string disposed in the wellbore. Accordingly, these surface treatment systems have inherent inefficiencies not only due to the excess fluid, but also due to the large power requirements used in pressurizing this treatment fluid. Also, placement is not always accurate or confined to a specific area leading to large segments being treated unnecessarily.